There is increasing demand in the oil and gas industry for higher performance thermal coatings to insulate and protect off-shore transport conduits operating at high temperatures in water depths above 1,000 meters. In order to maintain the conduit at the required operating temperatures at these depths, the coatings must have low thermal conductivity to prevent the formation of hydrates and waxes that would compromise pumping efficiency of the fluid in the conduit. Thermal conductivity is decreased through foaming the coating to some required degree, but the coating must maintain high enough thermal stability and compressive creep resistance to withstand the operating temperatures and hydrostatic pressures acting on the coating in deep water. Without sufficient compressive strength, the insulation will be compressed in thickness, thereby increasing thermal conductivity and altering the dimensions and the thermal and hydrodynamic performance of the system. Also, it is important that the coating remain sufficiently ductile after application on the conduit to prevent cracking during handling and installation, for example during reeling of the conduit onto a lay barge and subsequent deployment therefrom.
Multi-phase fluid flow is common in subsea fluid transport conduits, such as flowlines and risers. Two main concerns in such systems are the formation of gas-water hydrates and the deposition of wax. Both of these phenomena are related to the temperature of the fluid, and in extreme cases the conduit can become severely constricted or even blocked. This in turn can lead to reduced or lost production. In particularly serious cases this may lead to the need to replace sections of pipeline or entire systems with corresponding loss of asset value. Thermal insulation is used to provide controlled energy loss from the system either in steady state condition or in the case of planned and un-planned stoppage and thereby provide a reliable basis for operation.
For single-pipe flowlines and risers, using bonded external insulation, the mechanical loads as well as the requirements placed on the mechanical and thermal performance of thermal insulation systems normally increase with deeper waters. Hence, the traditional thermal insulation foam technology used in shallow waters and the associated design and test methodology may not be applicable to deep-water projects.
Current technologies include single pipe solutions, typically with insulation requirements in the heat transfer coefficient range of 3-5 W/m2 K, using polypropylene foam or polyurethane foam as the insulant, and so-called Pipe-In-Pipe systems wherein a second pipe surrounds the primary conduit, the annulus between the two pipes being filled with an insulating material.
Limitations and deficiencies of these technologies include:                Relatively high thermal conductivity of foamed polypropylene systems necessitating excessively thick coatings to achieve the required insulation performance, leading to potential difficulties in foam processing, potential issues with residual stress, difficulties during pipe deployment, and sea-bed instability.        Compression and creep resistance issues at high water depth leading to a change in buoyancy posing significant challenges in system design.        Excessive costs due to poor material cost versus performance capabilities or high transportation and deployment costs.        Deployment and operation disadvantages with Pipe-In-Pipe systems due to weight factors leading to buckling and weld failure if not properly addressed, and the need for high gripping loads during pipe laying.        
Therefore, there remains a need for improved coatings for thermal insulation and protection of fluid and/or gas transport conduits such as oil and gas pipelines, especially for off-shore transport conduits operating at high temperatures in water depths above 1,000 meters.